In the HVAC industry, purging refrigeration lines with nitrogen to eliminate oxygen prior to and during a brazing operation during installation or maintenance reduces or eliminates the formation of deleterious oxides. For example, when brazing copper, the combination of the heat applied and oxygen in the ambient air creates a chemical reaction that forms copper oxide. The oxide can form flakes that can become lodged in the thermal expansion valve of the HVAC system and cause system failure, or can foul system filters. Flowing nitrogen during brazing eliminates the oxygen and thus the formation of the oxides.
In such a purging and brazing operation, it is important to have the correct amount of nitrogen flow in the system while avoiding the formation of these deleterious oxides. If too much nitrogen flows during brazing, pin holes can be created and a poor quality braze can result. If insufficient nitrogen flows during brazing, deleterious oxides can be formed.
Embodiments disclosed herein enable proper purging of a refrigerant system with nitrogen gas and ensure that the correct amount of nitrogen flows in the line during the brazing operation.